The present invention relates to a record stylus of the capacitance detection type.
Capacitance detection type record styli have been developed to detect, as capacitance variations, high density information stored on a disk record in the form of minute pits along spiral or concentric tracks. The conventional stylus comprises a hard, dielectric body such as diamond or sapphire and an electrode deposited on a rear surface of the dielectric body. The electrode extends to the bottom of the dielectric body which is made to slidably contact with the disk record which spins at considerably high speeds. Since the stylus electrode acts as a critical element for the detection of the recorded signal, its thickness should be commensurate with the length of the recorded bit and its width substantially corresponds to the width of the track.
To provide a passage for signals detected by the electrode the surface of the diamond is conventionally coated with a conductive layer and connected to the electrode. However, such coating requires that the surface of the diamond be polished to mirror finish to assure firm bonding between the two materials. This results in a long production time. Furthermore, since the narrow electrode makes a point contact with the conductive layer on the diamond, disconnection can occur in the conductive path or the electrical resistance thereof can increase if a shock is applied to the stylus.